[blitzar]

Average speed in central london is 7mph.

To be fair, cars are on demand, unlike tube where waiting times can reach an outrageous 5 minutes.

[rsj_hn]

But central London is a tiny portion of London, and the slow speeds are very common for busy downtown areas of large cities. Despite excellent public transportation, 54% of London households own at least one car - not too much different from the number for Newark, NJ (60%).

https://content.tfl.gov.uk/technical-note-12-how-many-cars-a...

[blitzar]

The London orbital motorway the M25, definately not central London, with its majestic 12 lane sections boasts an average speed of 25mph.